In recent years, development of electric vehicles that travel with power of electric motors like an electric vehicle, a hybrid automobile, or a fuel cell automobile, and introduction of the electric vehicles into the market have been rapidly advanced. In many of the air conditioners in the electric vehicles as above, electric compressors using electric motors are also used as compressors which compress and feed refrigerants.
Further, in some of the air conditioners of automobiles which travel with the power of internal combustion engines, electric compressors are used to remedy reduction in drivability accompanying interruption of electromagnetic clutches, in place of the compressors which are driven by the internal combustion engines for traveling via the electromagnetic clutches.
As the electric compressors as above, encapsulated type electric compressors each integrally containing a compression mechanism and an electric motor in a housing are adopted, and many encapsulated type electric compressors in which electric power inputted from power supplies is supplied to electric motors via inverters, and the rotational speeds of the compressors can be variably controlled in accordance with air-conditioning loads are adopted.
In some of the electric compressors which are driven via inverters as above, the inverters and the electric compressors are integrated by housing and installing control circuit boards and the like configuring the inverters in the inverter boxes integrally molded on the housing outer peripheries of the electric compressors, and electrical components such as smoothing capacitors and coils which suppress electromagnetic noise are housed inside the above described inverter boxes.
In this case, high heat-producing electrical components such as switching elements (IGBT, Insulated Gate Bipolar Transistor) of the inverters need to be cooled. An inverter box is of a completely encapsulated structure, and cooling air or the like cannot be introduced from an outside. Therefore, as disclosed in, for example, Patent Literatures 1 to 3, a heat-dissipating planar part configuring an outer wall of a housing is formed inside the inverter box, the heat-producing electrical component is caused to abut on the heat-dissipating planar part, and by cold heat of the refrigerant flowing inside the housing, the heat of the electrical component is dissipated and cooled.
In each of the inverter-integrated electric compressors described in Patent Literatures 1 and 2, a heat-dissipating planar part is formed on a bottom surface of an inverter box, a heat-producing electrical component such as IGBT is installed on a top surface of the heat-dissipating planar part, a control circuit board is installed parallel above the electrical component via a space, and a pin terminal which extends upward from the electrical component is soldered to the control circuit board. In Patent Literature 1, the electrical component is pressed against the heat-dissipating planar part by the elastic force of an elastic member interposed between the control circuit board and the electrical component, whereas in Patent Literature 2, the electrical component is fastened to the heat-dissipating planar part with a vis. As a result of the above, the heat of the electrical components is dissipated to the heat-dissipating planar part sides.
Further, in the inverter-integrated electric compressor described in Patent Literature 3, a metal board is fixed onto a heat-dissipating planar part formed on a bottom surface of an inverter box, a heat-producing electrical component is loaded on the metal board, a control circuit board is installed parallel above the electrical component via a space, and the heat of the electrical component is dissipated to the heat-dissipating planar part side via the metal board.